a boil or other swelling or growth on the skin, especially a sebaceous cyst. Wen definition is - an abnormal growth or a cyst protruding from a surface especially of the skin. 7 days ago · A wen is the old word for a sebaceous cyst. Wen definition: a sebaceous cyst , esp one occurring on the scalp | Meaning, pronunciation, translations and examples. A term used to describe a type of Malaysian made kimchi.